US1583240A - Telephone system - Google Patents

Description

May 4 1926.

- J. wlcKs TELEPHONE SYSTEM 7 Filed Sept. 1 7, 1925 2 Sheets-Sheet 1 May 4 162s. 1,533,240

. J. WICKS I TELEPHONE SYSTEM Filed Sept. 17, 1923 2 Sheets-Sheet 2 Patented May 4, 1926.

UNITED STATES PATENT OFFICE] I JOHN WICKS,.OF OAK PARK, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T0

AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE.

TELEPHONE SYSTEM.

Application filed September 17, 1923. Serial No. 663,013.

To all whom it may concern: I Be it known that 1, JOHN ions, a citizen of the United States of America, and a resident of Oak Park, Cook County, and State of Illinois, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification. 7

The present invention relates to telephone systems in general, but is concerned more particularly with such systems as have special means for informing the operator of the class to which the calling subscriber belongs.

This case may be considered an improvement on the system disclosed in Patent No. 1,281,112, granted to Willis, October 8, 1918. This 'Willis patent discloses means for ap' prising the toll recording operator of the class of the calling line by impressing av dis tinctive tone on the private normal conductor of the calling line, which tone is led over the release trunk conductor when the connection is set up and is placed across the line the talking circuits, thereby giving rise to' undesirable noises during conversation. Accordingly, it is an object of the present invention to provide new and improved arrangements for placing the distinctive tone on the talking circuit only at the correct time and in such a manner as to avoid getting the tone accidentally on another con nection.

A further object of the invention which naturally follows from the carrying out of the preceding one, is to limit the time during which the distinctive tone current is flowing, thereby permitting much smaller and more easily maintained sources of tone current to be used.

There are various other objects of the invention which are concerned mostly with the circuit details employed and which will be fully appreciated upon a further perusal of the specification.

ing Figs. 1 and 2, which show by means of the usual circuit diagrams a suflicient amount of the apparatus employed in a system embodying the features of the invention to enable the same to be understood and the utility of the invention to be appreciated. Fig. 1 shows the substation A, the associated line of which terminates at the exchange in the line switch C, which has access to selectors, such as E. The selector E has ac cess on one level to trunks extending to the oflice in which the toll recording operator is located, one of these trunks being shown in 'Flg. 2. Fig. 1 shows also the intermediate distributing frame IDF, by means of which the normal conductors ofthe line may be cross connected to the proper discriminating tone, depending upon the class to which the line may be assigned from time to time.

This drawing shows also the three marginal relays 74, 75, and 76, together with, the dis,- criminating tone transformers 77, 78, and 79 and the associated equipment.

The apparatus shown having been thus described briefly, the system can probably debest understood now from a detailed description of 'the manner in which a call to the toll recording operator is handled. For this purpose it will be assumed that the subscriber at substation A desires tomake a long distance call and accordingly'he must first call the toll recording operator.

When the receiver is removed at substation A, line relay 14 energizes over line conductors 11 and 12. Upon energizing, line relay 1 1 places ground on private normal conductor 10 at armature 20, thereby closing a circuit through the jumperS on the intermediate distributing frame IDF for the marginally adjusted relay 74:. Relay 74, however, does not energize at this time owing to its marginal adjustment. As a further result of ground being placed on the private normal conductor 10, a circuit is closed for switching relay 13 in series with stepping Referring. now to the drawings compris magnet 15. As a further result of theenergization of'line relay 14:,test' wiper 22 is connected to the unction of switching relay 13 and stepping magnet 15 atarmature 19.6

In case the trunk .upon which the wipers of the switch are standing is idle, switching relay 13 energizes immediately. Assuming the trunk to be busy, however, switching re lay 13 is short-circuited by the ground potential encountered by test wiper 22 on' the busy test contact and does not energize, and the wipers are rotated step by step by the buzzer-like action of stepping magnet 15, which is operated through test wiper 22. When an idle trunk is reached, which trunk it will be assumed is the one terminating in bank contacts 24-26, inclusive, switching relay 13, being no longer short-circuited, energizes in series with stepping magnet 15. Stepping, magnet 15, however, does not energize at this time on account of the high re"- sistance of switching relay 13. Switching relay .13, upon energizing, opens a point in the test circuit and prepares the holding circuit at armature 17, and at armatures 16 and 1:8 disconnects line conductors 11 and 12 from the winding of line relay 14 and ground, and extends them by way of wipers 21 and 23, bank contacts 24 and 26, conductors 27 and 29, armatures 57 and 60 and their resting contacts, to the upper and lower windings of line relay 35' of the selector E.

Line relay 35 now energizes over the calling subscribers loop and closes at armature 51 a circuit for release relay 36. Upon energizing, release relay 36 opens a point in the circuit of release magnet 44 and prepares a circuit for vertical magnet 40 at armature 53, and at armature 52 places ground on release trunk conductor 28, thereby closing the usual holding circuit for switching relay 13 of the line switch C before slow-acting line relay 14 has had time to deene-rgize.

When the calling subscriber operates his calling device in accordance with the digit necessary to trunk the call to the toll recording operator, the circuit of line relay 35 is opened a corresponding number of times. Eachtime line relay 35 deenergizes in response to one of the interruptions thereby produced, it closes a circuit for vertical magnet 40 as follows: from ground by way of the resting contact of armature 59 and said armature, armature 51 and its resting contact, armature 53 and its working contact, relay 37, and vertical magnet 40 to battery. By the operation of vertical magnet 40, the wipers 61-63, inclusive, are raised opposite the desired level of bank contacts. Relay 37 is energized in series with vertical magnet 40 and, being slow-acting, retains its armature attracted throughout the vertical movement. As a result of the energization of relay 3-7, a circuitis closed at armature 54 for stepping relay 39 by way of oft normal contacts '43 (which close upon the first vertical step) and interrupter contacts 42. Stepping relay 38, upon energizing, closes a locking circuit for itself at armature 55,

and at armature 56 prepares a circuit for rotary magnet 41. I

At the end of the vertical movement, slowacting relay 37 deenergizes and completes the circuit of rotary magnet 41 at armature 54. Rotarymagnet 41, upon energizing, advan'ce's the wipers 61-63, inclusive, into engagement with the first set of bank contacts in the selected level, and, near the end of its stroke, opens the circuit of stepping relay 38 at interrupter contacts 42. Stepping relay 38, upon deenergizing, opens the circuit of rotary magnet 41 at armature 56, whereupon rotary magnet 41 deenergizes alsoand closes its interrupter contacts 42 again. In case the trunk terminating in the first set of bank contacts is idle, switching relay 39 energizes immediately. Assuming the trunk to be busy, however, switching relay 39 is short-circuited by the round potential encountered by test wiper 62, and stepping relay 38 energizes from this same ground potential and closes the circuit of rotary magnet 41 again, whereupon the switch wipers are rotated into engagement with the next set of bank contacts. This alternate operation of stepping relay 38 and rotary magnet 41 continues until an idle trunk is reached, which trunk it will be assumed is the one terminating in bank contacts 64-66, inclusive, whereupon switching relay 39, being no longer short-circuited, energizes in series with stepping relay 38. Stepping relay 38,

however, does not energize at this time on account of the high resistance of switching. relay 39. Switching relay 39, upon energizing, opens a point in the test circuit and prepares the holding circuit at armature-58; disconnects ground from armature 51 of line relay 35 at armature 59, thereby opening the circuit of release relay 3'6: and at arnratures 57 and 60 disconnects conductors 27 and 29 from the windings of line relay 35, and extends them by way of wipers 61 and 63, bank contacts 64 and 66 and trunk conductors 67 and 69 to the windings of line relay 101 of the trunk circuit TC. Line relay 101, upon energizing, closes a circuit for release relay 102 at armature 104, whereupon release relay 102 energizes and places ground on release trunk conductor 68 at armature 106, thereby establishing the usual holding circuit for-the switching relays of the line switch C and the selector E before the slow acting release relay 36 of the selector E hasv had time to deenergize.

As a further result of the energization of line relay 101, ground is placed on the lower winding of the marginally adjusted back bridge relay 103 at armature 105, thereby closing a circuit over the inter-office trunk conductors 110 and'111 and through resistance 135 and relay 134 to the toll recording operators position. Relay 134 energizes over this circuit, but back bridge relay 103 does not energize on account of the high resistance 135. Relay 134, upon energizing, closes at armature 136 a circuit for the answering lamp L, which circuit includes spring 131 of the key K and its lower contact, and spring 133 and its lower contact. The lamp L accordingly becomes lighted to inform the operator of the call.

The operator, upon noting the lighted condition of the lamp L, manipulates her listening key K, thereby connecting her listening taps to the trunk conductors 110 and 111. In order to hear the tone the operator throws the key K in such a direction as to operate springs 131 and 132. Spring 131 disconnects the lamp L and prepares another circuit for itand spring 132 places a. shunt around the high resistance 135, whereupon the marginally adjusted back bridge relay 103 of the trunk circuit TC energizes and at armature 107 places the booster battery 109 through the resistance 108 on the release trunk conductor 68 and disconnects direct ground therefrom. This booster battery is poled opposite the regular exchange battery and accordingly the current flows through the two in series, thereby maintaining the switching relay 39 of the selector E and switching relay 13 of the line switch C energized more firmly than before. This booster battery, being at a potential below ground, also serves to maintain the connection busy during the time it is applied. The reason for applying the booster battery, it will be understood, is to operate the marginally adjusted relay 74, Fig. 1, which relay, upon energizing, connects the common conductors extending from the secondary side switch of the tone transformer 77, to the line conductors of the calling line. This tone is accordingly transmitted over the established connection to the toll recording operator and informs her of the class to which the calling line belongs. After the operator has noted the class of the calling line, she throws the key K to the opposite position, thereby restoring the springs 131 and 132 and operating spring 133. Spring 133 now takes over the function of spring 131, and spring 132 reinserts the resistance 135 in the circuit, whereupon relay 103 of the trunk circuit TC deenergizes and connects the release trunk conductor 68 back to ground again. hen this occurs the marginally adjusted relay 74, Fig. 1, deenergizes and disconnects the tone from the calling line.

The operator may now converse with the calling subscriber and learn his wants and make the necessary ticket to pass to the toll operator, provided of course that the calling line is entitled to the class of service desired.

When the receiver is replaced at substation A after the conversation with the toll recording operator is terminated, linejrelay 101 of the trunk circuit TC deenergizes and opens the circuit of relay 134 of the oper ators circuit OC. Relay 134 thereupon deenergizes and completes a circuit for the lamp L which includes the'upper contact of spring 133 of the key K and said spring, lower contact of spring 131 and said spring, and armature 136 and its resting contact- The operator, upon noting the lighted condition of the lamp L, knows that the calling subscriber has now replaced his receiver and she accordingly restoresthe key K.

tion of switching relay 39 of the selector E results in a circuit being closed at armature 59 and through armature 51 and its resting contact, armature 53 and its resting contact, and ofi' normal contacts 45 for release magnet 44. Release magnet 44 thereupon energizes and the wipers of the switch E are restored to normal position in the usual manner, whereupon the circuit of release magnet 44 is opened at off normal contacts 45.

From the above it will be seen how the operator is enabled to listen to the tone placed on the line of substation A at the exchange in accordance with the class thereof. It is perfectly obvious if the line of substation A is later changed to another class, the appropriate connection may be "made at the IDF and the normal conductors will be connected to a relay, such as or 76, depending upon the class to which the line belongs.

It will be seen that I have devised a very efficient means of informing the toll recording operatorof the class of the calling line and that a great saving in the consumptionof the tone current is effected inasmuch as the current flows only during the short period of time that the toll recording operator is listening, instead. of during the entire time the connection is established, as has been the practice heretofore. It will be seen also that the discriminating tone is applied in such a manner that there is no likelihood of the tone being heard on any line other than the calling line.

What is claimed is:

1. In a telephone system, a calling line, an operators switchboard, means for extending a connection from said line to said switchboard,v a source of tone current, and means individual to said line for connecting said source thereto, said individual means being controlled from said operators switchboard over said connection.

2. In a telephone system, a calling line, an operators switchboard, means for extending a connection from said line to said switchboard, a source of tone current, and means individual to said line for connecting said source thereto, said individual means being controlled over the established connection:

3. In a telephone system, a plurality of lines divided into classes, a separate tone circuit for each class, means individual to each of said lines for connecting the associated line with the particular tone circuit corresponding to its class, means for setting up a connection from a calling line to a desired point, and means controlled from said point over said connection for controlling said individual means.

4. In a telephone system, a calling line, an operators position, means including auto matic switches for extending a connection from said line tosaid operators position, a

holding conductor for maintaining saidswitcl-ies operated, a source of tone current, means individual to said line for connecting said source thereto, and means for controlling said individual means over said holding conductor from said operators position,

5. In a telephone system, a calling line, an operators position, means including automatic switches for extending a connection from said line to said operators position, a

holding conductor for maintaining said JOHN WIOKS.

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